Is the term urban ecology an oxymoron? asks Eric Strauss, director of the Environmental Studies Program and science director of the Urban Ecology Institute, in his lecture at the Weston Observatory. With 75 percent of the U.S. population and half of the worlds population living in urban areas, the sustainability of urban ecological systems is of paramount importance, says Strauss, who suggests we must stop thinking of the city as a problem but as a solution with respect to environmental and social challenges.